In a radio communication system, a radio base station forms a cell that is an area where the radio base station can perform communication, allocates a communication channel to a radio terminal located within the cell, and executes radio communication with the radio terminal via the allocated communication channel. The radio base stations generally allocate, to radio terminals, communication channels having frequencies different between adjacent cells, thereby preventing occurrence of interference.
Meanwhile, to improve frequency utilization efficiency and cell throughput, there has been proposed a technique called fractional frequency reuse (FFR) in which radio base stations use the same frequency as a part of frequencies used by adjacent cells, and thereby purposely use communication channels affected by interference from another radio base station, radio terminal or the like (hereinafter referred to as a “interference source”) (see Patent Document 1, for example).
In such FFR, the radio base station allocates a first communication channel more affected by the interference from an interference source to a radio terminal with good reception quality such as reception SINR, more specifically, a radio terminal located near the center of the cell. The first communication channel is a communication channel using the same frequency as that of an adjacent cell.
Meanwhile, the radio base station allocates a second communication channel less affected by the interference from the interference source to a radio terminal with poor reception quality, more specifically, a radio terminal located near the cell edge. The second communication channel is a communication channel using a frequency different from that of an adjacent cell.